Functions and Contracts in Solidity


Solidity is a high-level programming language that is used to write smart contracts on the Ethereum blockchain. Smart contracts are self-executing contracts that are automatically enforced when certain conditions are met. In Solidity, two of the most important components that play a critical role in the development of smart contracts are functions and contracts.

Functions in Solidity

A function in Solidity is a set of instructions that can be executed when called by another part of the code. Functions can be used to perform specific tasks or calculations, and they can be customized to accept inputs and return outputs. Functions in Solidity are defined using the function keyword, followed by the name of the function and any input parameters.

For example, here is a simple function in Solidity that adds two numbers together:

function addNumbers(uint a, uint b) public pure returns (uint) {
    return a + b;

In this example, the function is named addNumbers and it takes two input parameters of type uint. The function is defined as public, which means that it can be called by any other part of the code. The pure keyword indicates that the function does not modify the state of the contract, and the returns keyword specifies that the function will return a value of type uint.

Contracts in Solidity

A contract in Solidity is a collection of functions and data that are stored on the Ethereum blockchain. Contracts are defined using the contract keyword, followed by the name of the contract and any variables or functions that it contains.

For instance, here is a simple contract in Solidity that stores a single integer value:

contract MyContract {
    uint myNumber;

    function setNumber(uint newNumber) public {
        myNumber = newNumber;

    function getNumber() public view returns (uint) {
        return myNumber;

In this example, the contract is named MyContract and it contains two functions: setNumber and getNumber. The contract also contains a variable named myNumber, which is of type uint. The setNumber function is used to set the value of myNumber, while the getNumber function is used to retrieve the value of myNumber.

Best Practices for Structuring Your Code

When writing Solidity code, it is important to follow best practices to ensure that your code is secure and efficient. Here are some tips for structuring your Solidity code:

  • Use descriptive function and variable names to make your code easier to understand.
  • Use comments to provide context and explanation for your code.
  • Avoid using global variables, as they can be accessed and modified by anyone on the blockchain.
  • Use the require keyword to validate inputs and ensure that your code executes correctly.
  • Use the view and pure keywords to indicate whether your function modifies the state of the contract or only returns a value.
  • Use the emit keyword to trigger events when certain conditions are met.

By following these best practices, you can write Solidity code that is secure, efficient, and easy to understand.

In summary, functions and contracts are two of the most important components in Solidity, and they play a vital role in the development of smart contracts. By following best practices when structuring your Solidity code, you can ensure that your code is secure, efficient, and easy to understand.

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